Field Electrical Conductivity (EC) Mapping of a Selective Irrigated Units at Northern Al-Jazirah Irrigation Project, Iraq Using GIS and GPS Techniques

Abstract

The application of apparent electrical conductivity (ECa) to agriculture is due to the soil salinity measurement, which represents a problem in arid areas associated with irrigated agricultural land and shallow aquifers. The purpose of this paper is to apply the modern geo-referenced technology by using LandMapper ERM-02 device and GPS receiver to measure manually the soil ECa of (50) sites in the irrigated units N15 and N16 at Northern Al-Jazirah Irrigation Project. The remote sensing data, the map of Northern Al-Jazirah Irrigation Project and GIS are utilized to support the analysis and the spatial information of the measured ECa data. A kriging interpolation method is adopted to predict the ECa values at non-surveyed location and to create the final soil ECa map. The results of the field measurements show that the ECa in the study area varies between 2.66 to 51.74 dS/m. The results of the geostatistical analysis and the regression function of the ECa data indicate a decrease in the errors associated with the soil ECa interpolated map with increasing the values of soil ECa in the study area. However, the studied method is less accurate than the laboratory based soil sample analysis method, but for a quick estimate of soil salinity, this method is highly satisfied.